At present, Freon-based refrigerants that have stable properties and are easy to be handled are used as refrigerants of an apparatus having a refrigeration cycle such as a freezer, a refrigerator and an air conditioner. However, although the Freon refrigerants have stable properties and are easy to be handled, it is said that the Freon refrigerants destroy the ozone layer, and since the Freon refrigerants adversely affect the global environment, the use of the Freon refrigerants will be entirely prohibited in the future after a preparatory period of time.
Among the Freon-based refrigerants, hydro fluorocarbon (HFC) refrigerants do not seem to destroy the ozone layer, but they have properties to facilitate the global warming. Especially in Europe where the people is concerned about environmental problems, there is a tendency to prohibit the use of this refrigerant also. That is, there is a tendency that the use of the Freon refrigerants that are artificially produced is prohibited, and natural refrigerants such as hydrocarbon are used as in the past.
However, since such natural refrigerants are flammable, it is necessary to prevent the explosion or ignition of the refrigerants for safety.
As a method for preventing the explosion or ignition when hydrocarbon refrigerant is used, it is proposed to remove, isolate or keep away from a fire source (e.g., Japanese Patent Applications Laid-open No.H7-55267 and No.H8-61702). For preventing the explosion or ignition of the hydrocarbon refrigerant, it is also proposed to convert the refrigerant into a non-flammable refrigerant (e.g., Japanese Patent Application Laid-open No.H9-59609).
However, although it is effective, for safety of the air conditioner, to remove, isolate or keep away from the fire source, it can not be said that this is a fundamental solution. Further, it is extremely difficult to convert the refrigerant into the non-flammable refrigerant, and a conclusive method has not yet been proposed.
To solve the above problem, according to the present invention, there is proposed an air conditioner using a flammable refrigerant, in which a gas sensor monitors leakage of the refrigerant out of the air conditioner, and if the leakage is detected by the gas sensor, the refrigerant in a refrigeration cycle is positively discharged from a discharge portion to outside to the atmosphere, thereby removing the refrigerant charged in the refrigeration cycle.
With the above structure, the leakage of a flammable refrigerant is monitored, and after the leakage is detected, the refrigerant is positively discharged to the safe atmosphere, e.g., to the side of an outdoor unit, and even if the refrigerant is leaked at the side of an indoor unit, it is possible to suppress the leakage to a certain level.